Why Untested Systems Fail Perfectly — Right When You Need Them
Introduction — maintenance records do not equal reliability
Most shipboard electrical failures occur in systems that were:
- installed correctly
- maintained “to schedule”
- documented as compliant
The difference between compliance and reliability is testing philosophy. Maintenance that does not stress systems under realistic conditions creates false confidence.
What electrical maintenance actually needs to prove
Electrical maintenance must answer:
- Will this system operate under fault?
- Will protection act before damage?
- Will insulation survive heat and moisture?
- Will control power remain stable during disturbance?
Tick-box maintenance answers none of these.
Testing methods — what they reveal and what they hide
Insulation Resistance (IR) testing reveals moisture ingress but not insulation ageing under load.
Polarisation Index (PI) and DAR show insulation behaviour over time but can be misleading on modern materials.
Thermography reveals heat — the universal precursor to failure — but only when conducted under realistic load.
Hipot and VLF tests can detect weaknesses, but performed incorrectly they can create failures, not prevent them.
Testing must be chosen with intent, not tradition.
🔧 Regulatory anchors (explicit)
SOLAS II-1 Reg. 45 — maintenance to prevent fire and shock
IEC 60092 series — testing expectations for marine electrical systems
Class rules require evidence of periodic testing, not just inspection
Investigations often ask not whether tests were done, but what the tests actually proved.
🔻 Real-World Case: Generator Failure After “Completed Maintenance” — North Sea PSV (2015)
A North Sea platform supply vessel suffered generator failure shortly after scheduled maintenance.
Findings showed:
- insulation tests passed at ambient temperature
- no load testing conducted
- cooling airflow restrictions unnoticed
- failure occurred under sustained operational load
Maintenance was compliant.
Testing was insufficient.
CMMS — memory without understanding
Computerised Maintenance Management Systems (CMMS) are powerful tools for:
- tracking intervals
- recording history
- scheduling tasks
They do not replace engineering judgement. A CMMS cannot decide:
- when to test harder
- when trends indicate failure
- when “still passing” is no longer acceptable
CMMS preserves memory. Reliability requires interpretation.
Professional ETO mindset
A professional ETO asks:
- What failure would this test not reveal?
- Was this system ever tested at full load?
- What trends are hidden behind “pass”?
- What assumptions does the maintenance plan make?
Maintenance should challenge systems, not reassure people.
Knowledge to Carry Forward
Electrical systems fail at their weakest, least-tested point. Maintenance that avoids stress avoids truth. Testing that does not resemble reality produces confidence without resilience.
Ships don’t fail because maintenance was skipped.
They fail because maintenance was believed too easily.
Tags
ETO, Marine Electrical Maintenance, CMMS, Insulation Testing, Thermography, IEC 60092, Reliability Engineering